控释尿素不同条施深度下鲜食玉米产量和氮素利用效应

Yield and Nitrogen Utilization Efficiency of Fresh Edible Maize Under Different Fertilization Depths of Control-release Urea

通过田间试验研究一次性施肥条件下控释尿素不同条施深度(0,5,10,15cm)对鲜食玉米产量、干物质积累变化、氮素利用率和土壤无机氮含量的影响,为控释尿素在鲜食玉米上的应用推广提供依据。结果表明:控释尿素施用深度的不同主要影响鲜食玉米抽雄至乳熟收获期的干物质积累,该阶段10,15cm深度下鲜食玉米的干物质积累速率和积累量显著高于0,5cm。随着控释尿素施用深度的增加,鲜食玉米鲜穗产量、乳熟收获期植株总吸氮量以及氮肥偏生产力、氮肥农学利用效率和氮肥表观利用率均呈现递增趋势,与0cm相比,15cm深度处理的鲜穗产量和收获期植株总吸氮量分别显著提高13.3%和53.0%,氮肥偏生产力从70.9kg/kg增加到80.4kg/kg,氮肥农学利用效率从6.8kg/kg增加到16.3kg/kg,氮肥表观利用率从3.3%提高到33.7%;10cm深度处理仅较0cm处理显著提高了植株总吸氮量和氮肥表观利用率,而5cm深度处理的鲜穗产量、乳熟收获期植株总吸氮量、氮肥偏生产力、氮肥农学利用效率和氮肥表观利用率与0cm处理间均无显著差异。抽雄期叶片光合特性测定结果表明,与不施氮(CK)相比,控释尿素的施用显著提高了单株叶面积、叶面积指数和穗位叶净光合速率,与0cm相比,15cm深度处理的单株叶面积、叶面积指数、叶片净光合速率、蒸腾速率和胞间CO2浓度均有不同程度的提高。关键生育期的土壤无机氮测定结果表明,控释尿素施用深度的增加可以提高拔节期、抽雄期和乳熟收获期行间(施肥部位)0—20cm土层、抽雄期和乳熟收获期行间(施肥部位)20—40cm土层以及乳熟收获期玉米种植行(非施肥部位)0—20cm的土壤无机氮含量。可见,控释尿素深施能够提高鲜食玉米抽雄期以后的土壤供氮能力和改善叶片光合特性,促进干物质积累和氮素吸收,从而提高氮肥利用率和鲜穗产量。试验设置条件下,控释尿素最佳的施用深度为15cm。

In order to provide the basis for the application and popularization of control-release urea（CRU）in fresh edible maize,field experiments were conducted to study the effects of CRU applied in different depth（0,5,10 and 15 cm）on yield,dry matter accumulation,nitrogen utilization efficiency of fresh edible maize and inorganic nitrogen content in soil.The results showed that different application depth of CRU mainly affected the dry matter accumulation during the periods of tasseling to harvesting,moreover fertilizing CRU in10 cm and 15 cm depth produced significant greater dry weight than fertilizing in 0 cm and 5 cm depth.Fresh ear yield,total nitrogen uptake of plants during milk ripening period,partial factor productivity（PFP）,ag-ronomic efficiency（AE）and apparent recovery efficiency（RE）of nitrogenous fertilizer all increased with the increasing of CRU application depth.Compared with fertilizing in 0 cm,fertilizing CRU in 5 cm depth had no effect on fresh ear yield,total nitrogen uptake,PFP,AE and RE of nitrogenous fertilizer.Fertilizing CRU in 10 cm depth significantly increased total nitrogen uptake and RE.However,fertilizing CRU in 15 cm depth significantly increased fresh ear yield and total nitrogen uptake by 13.3% and 53.0%,respectively,and increased PFP from 70.9 kg/kg to 80.4 kg/kg,increased AE from 6.8 kg/kg to 16.3 kg/kg,and increased PE from 3.3%to 33.7%.The results of leaf photosynthetic characteristics determination during tasseling stage indicated that application of CRU could increase the leaf area per plant,leaf area index and the photosynthetic rate of ear leaf.Moreover,compared with the 0 cm fertilization,fertilizing CRU in 15 cm depth increased the leaf area per plant,leaf area index,photosynthetic rate,transpiration rate and intercellular CO2 concentration of ear leaf.The results of soil inorganic nitrogen test at key growth stages indicated that the increasing of CRU application depth significantly increased inorganic nitrogen content in 0—20 cm soil layer of fertilizer band at jointing,tasseling and harvest stages,and increased it in 20—40 cm soil layer of fertilizer band at tasseling and harvest stages,and increased it in 0—20 cm soil layer of non-fertilizer band at harvest stage.These results indicated that deep application of CRU could significantly improve the soil nitrogen supplying ability and leaf photosynthetic characteristics after tasseling stage,and promote dry matter accumulation and nitrogen absorption,and thus improve yield and nitrogen utilization efficiency of fresh edible maize.Under the conditions of this study,the optimal application depth of CRU was 15 cm for fresh edible maize.